1. Field of the Invention
The present invention relates generally to an imaging microscope and, more particularly, to a microscope for examining the amount and direction of incident radiation such as neutrons or the like, or for examining cellular tissue or other specimens in a hospital or laboratory environment, and which performs imaging of a sample using a line sensor.
2. Discussion of Related Art
In recent years, there has been an increase in the number and types of facilities which produce radiation for various reasons, such as hospitals, radiotherapy clinics, and atomic power plants. Associated with this increase is a heightened need for measuring personnel at such locations for exposure to harmful amounts of radiation.
Conventionally, radiation exposure testing has involved attaching a sample material to a person's coat or other article of clothing to measure an amount of incident radiation on the sample, as disclosed in JP-A-11-174157, JP-A-2001-42038, and numerous other references. The measuring means employed by such devices is generally as follows.
The sample is formed of an organic plastic, or the like, which, if exposed to radiation, suffers damage in molecular bonds. If the damaged part is etched with a predetermined solution, it produces fine etch pits. The etch pits are different in shape depending upon the amount or direction of incident radiation. Accordingly, by examining and adding the form of etch pits caused on the sample by use of a microscope, measurement of the amount and direction of incident radiation can be made.
Meanwhile, in medical institutions such as hospitals or university laboratories, examination of cellular tissue such as cancerous cells and the like is frequently conducted using optical and other types of microscopes.
While it is possible to conduct visual examination, determination, or the like, of etch pit forms, cellular tissue, or the like, using an optical microscope, it entails a huge labor cost and constitutes a great burden to conduct such examination and determination on a large number of samples. Furthermore, variation can occur in such examinations or determinations due to the individual differences between persons who conduct the examinations or make such determinations. For this reason, it has been proposed to attach a two-dimensional charge coupled device (“CCD”) camera to a microscope so that an image acquired by the CCD camera is displayed on a computer screen to enable examination of the amount and direction of incident radiation, or to enable the examination of cellular tissue or other specimens. In addition, image processing means may also be used to perform automatic calculation of the amount and direction of incident radiation or the determination of a range, advancement, type, or the like, of cancerous cells or other specimen characteristics based on an image obtained by the microscope.
However, the two-dimensional CCD sensor that is used in the conventional CCD camera is provided vertically and horizontally with a planar array of devices, such as 600×600, such that there are approximately 3.5 billion charge coupled devices having one side length of 21 micrometers, for example. Accordingly, in the case of taking an image with a magnification of 30×, for example, it is possible to take, at one time, an image only in a range of 21 micrometers×600 pieces/30=0.42 square millimeters.
Consequently, there is a need to repeat imaging of the same sample while moving the 0.42-millimeter-squared imaging range sequentially from one end to the other thereof. In the meanwhile, in order to obtain a clear image screen, there is a need to stop the sample each time after moving it by one screen in order to take an acceptable image. It takes a great deal of time to take an image of samples within a predetermined region. Furthermore, in order to obtain a clear image, it is necessary to correctly set a focal length for each image. This is typically done using a two-dimensional CCD sensor to automatically set a focal length as is widely done in CCD cameras. However, the following problem exists in such automatic focal-length setting means. Namely, the focal adjustment on the typical CCD camera using a two-dimensional CCD sensor is set at a focal position where the taken image is the sharpest, i.e. exhibits intense contrast, which is an in-focus position. Accordingly, to carry out focal adjustment with a conventional two-dimensional CCD sensor, searching for the greatest contrast point requires examination of a maximum contrast value by performing measurements around a given focal point. Because of the need to examine around the focal point, there is a disadvantage in that a large amount of time is required for focal adjustment.
In addition, in order to obtain a clear image there is a need to accurately and swiftly adjust three factors including inclinations in both the X and Y directions and average focal length. The automatic focus adjustment used in a conventional microscope apparatus is performed by driving the objective lens using a motor or the like, or by using a focus adjusting drive means having two types of drive means including an inclination adjusting drive means and a focus adjusting drive means provided on the support base. When imaging of a sample is performed, there is a need to take an image by setting a particular range in the sample. Since the size often differs depending on the sample, there is a need to take an image within a range that does not jut out from the periphery of the sample, which may happen whenever changing of the sample takes place. Consequently, there is a need to set a start point 11a and end point 11b (see FIG. 7) of an imaging range before taking an image. Furthermore, when taking an image of a cellular tissue such as cancerous cells, a part of the sample where a cell of interest exists must be selected to set an image range.
Accordingly, it is an object of the present invention to provide a microscope apparatus capable of swiftly and accurately taking an image within a predetermined range of a sample when conducting an examination of a sample for purposes such as detecting the amount and direction of incident radiation or when examining cellular tissue or the like.